Conventionally, metal closures include an annulus of sealing compound, which is inserted into the closure after fabrication. A PVC organisol coating must be applied to the internal surface of the closure shell, to promote adhesion of the compound to the closure cap. The sealing compound is arranged to provide a sealing interface between the container and the closure. However, there has been growing concern about migration of chemicals from the sealing compound into the product held within the container. This has been a particular concern for containers of food product especially for containers of baby food. U.S. Pat. No. 6,832,692 seeks to overcome this problem by providing an insert having a gasket portion of soft pliant material, to provide sealing, and a tamper evident band of much stiffer material to provide rigidity to the insert. The insert is inserted into a metal closure shell. However, this closure is relatively expensive to manufacture and is not suitable for use with a simple metal twist-off closure or lug cap having an internal peripheral curl on the closure shell.
An alternative closure arrangement has been proposed in DE 2813940 and FR 79000608 utilising a resilient stopper and an outer cap adapted to lock the stopper onto a container neck. A disadvantage of these arrangements is that the outer cap must be destroyed upon first opening of the closure arrangement and therefore cannot be resealed on the container neck.